The EastEnders actress admits she never expected to return to the role of soldier Molly Dawes following the standalone episode on BBC One in 2013.

"We didn't know it would go to a series or anything like that," she told Digital Spy. "We were just really pleased and gobsmacked with how the first one went.

"I don't think we expected it to get the response that it got. So for them to offer us a five-part series, we were just blown away!"

Our Girl returns to screens on Sunday night with five new episodes and Lacey spent several months filming the show in South Africa.

Lacey on This Morning earlier today (Image: REX)

Speaking earlier today on ITV’s This Morning, she revealed how tough it was shooting the series in full military combat under the searing South African sun.

She explained: “It is really hard, actually. I think that was probably the toughest thing out of the whole job, just getting used to the heat and stuff.

"But we did a week's boot camp when we got there and we started in shorts and then gradually as the days went on we added our combat bottoms, and then the long sleeves, and then your osprey, and then your Bergen, and then your helmet. So as the week went on you sort of acclimatised to it."

But the actress humbly concedes her experience doesn’t compare to the real-life soldiers who risk their lives in war zones.

"It's such an eye-opener, when you try and experience something that's similar but nothing like the real thing,” Lacey said.

"I mean, just moving around is hard. If you imagine trying to get from A to B while being shot at, I just can't ... What they do is amazing."

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